Characterization of Peanut Oil Bodies Integral Proteins, Lipids, and Their Associated Phytochemicals

Structuration of lipid bases zero-trans and palm oil-free for food applications

This work evaluated structured lipids (SLs) through chemical and enzymatic interesterification (CSLs and ESLs). Blends of soybean oil and peanut oil 1:1 wt% were used, with gradual addition of fully hydrogenated crambe to obtain a final behenic acid concentration of 6, 12, 18, and 24 %. Chemical catalysis used sodium methoxide (0.4 wt%) at 100 °C for 30 min, while enzymatic catalysis used Lipozyme TL IM (5 wt%) at 60 °C for 6 h. Major fatty acids identified were C16:0, C18:0, and C22:0. It was observed that with gradual increase of hard fat, the CSLs showed high concentrations of reaction intermediates, indicating further a steric hindrance, unlike ESLs. Increased hard fat also altered crystallization profile and triacylglycerols composition and ESLs showed lower solid fat, unlike CSLs. Both methods effectively produced SLs as an alternative to trans and palm fats, view to potential future applications in food products.

Unveiling the applications of membrane proteins from oil bodies: leading the way in artificial oil body technology and other biotechnological advancements

Oil bodies (OBs) function as organelles that store lipids in plant seeds. An oil body (OB) is encased by a membrane composed of proteins (e.g., oleosins, caleosins, and steroleosins) and a phospholipid monolayer. The distinctive protein-phospholipid membrane architecture of OBs imparts exceptional stability even in extreme environments, thereby sparking increasing interest in their structure and properties. However, a comprehensive understanding of the structure-activity relationships determining the stability and properties of oil bodies requires a more profound exploration of the associated membrane proteins, an aspect that remains relatively unexplored. In this review, we aim to summarize and discuss the structural attributes, biological functions, and properties of OB membrane proteins. From a commercial perspective, an in-depth understanding of the structural and functional properties of OBs is important for the expansion of their applications by producing artificial oil bodies (AOB). Besides exploring their structural intricacies, we describe various methods that are used for purifying and isolating OB membrane proteins. These insights may provide a foundational framework for the practical utilization of OB membrane proteins in diverse applications within the realm of AOB technology, including biological and probiotic delivery, protein purification, enzyme immobilization, astringency detection, and antibody production.

Artificial oil bodies: A review on composition, properties, biotechnological applications, and improvement methods

In order to simulate the structure of natural oil body, artificial oil bodies (AOBs) are fabricated by the integration of oleosins, triacylglycerols (TAGs) and phospholipids (PLs) in vitro. Recently, AOBs have gained great research interest both in the food and biological fields due to its ability to act as a novel delivery system for bioactive compounds and as a carrier for target proteins. This review aims to summarize the composition and the preparation methods of AOBs, examine the factors influencing their stability. Moreover, this contribution focusses on exploring the application of AOBs to encapsulate functional ingredients that are prone to oxidation as well as improve efficiency involved in protein purification, renaturation and immobilization by reducing the complex steps. In addition, the improvement measures to further enhance the stability and efficacy of AOBs are also discussed. The application of AOBs is expected to be a big step towards replacing existing bioreactors and delivery systems.

Thermally treated peanut oil bodies as a fat replacer for ice cream: Physicochemical and rheological properties

This study investigates the potential use of peanut oil bodies as a fat replacer in ice cream. We explored the effects of different treatments, fresh (FOB), heated (HOB), and roasted (ROB) peanut oil bodies on ice cream preparation. Heat treatment altered the intrinsic protein profile on the oil bodies' surface, subsequently influencing the ice cream's properties. Notably, heat treatment increases the oil bodies' size and the absolute value of ζ-potential. The rheological analysis provided information about void volumes, indicating easier air incorporation during whipping for ROB (72 to 300 nm) than FOB (107 to 55 nm). ROB ice cream displays a high overrun and a lower melting rate compared to FOB ice cream. Moreover, thermal treatment reduces the beany flavors, n-hexanal, and 2-pentenylfuran. Overall, this study reveals peanut oil bodies as a promising platform for rational design of fat-substituted plant-based ice creams.

Effects of Roasting Temperatures on Peanut Oil and Protein Yield Extracted via Aqueous Enzymatic Extraction and Stability of the Oil Body Emulsion

Oil body emulsions (OBEs) affect the final oil yield as an intermediate in the concurrent peanut oil and protein extraction process using an aqueous enzyme extraction (AEE) method. Roasting temperature promotes peanut cell structure breakdown, affecting OBE composition and stability and improving peanut oil and protein extraction rates. Therefore, this study aimed to investigate the effects of pretreatment at different roasting temperatures on peanut oil and protein yield extracted through AEE. The results showed that peanut oil and protein extraction rates peaked at 90 °C, 92.21%, and 77.02%, respectively. The roasting temperature did not change OBE composition but affected its stability. The OBE average particle size increased significantly with increasing temperature, while at 90 °C, the zeta potential peaked, and the interfacial protein concentration hit its lowest, indicating OBE stability was the lowest. Optical microscopy and confocal laser scanning microscopy confirmed the average particle size findings. The oil quality obtained after roasting treatment at 90 °C did not differ significantly from that at 50 °C. The protein composition remained unaffected by the roasting temperature. Conclusively, the 90 °C roasting treatment effectively improved the yield of peanut oil extracted using AEE, providing a theoretical basis for choosing a suitable pretreatment roasting temperature.

Effects of Quillaja Saponin on Physicochemical Properties of Oil Bodies Recovered from Peony (Paeonia ostii) Seed Aqueous Extract at Different pH

Peony seeds, an important oil resource, have been attracting much attention because of α-linolenic acid. Oil bodies (OBs), naturally pre-emulsified oils, have great potential applications in the food industry. This study investigated the effects of extraction pH and Quillaja saponin (QS) on the physicochemical properties of peony oil body (POB) emulsions. POBs were extracted from raw peony milk at pH 4.0, 5.0, 6.0, and 7.0 (named pH 4.0-, 5.0-, 6.0-, and 7.0-POBs). All POBs contained extrinsic proteins and oleosins. The extrinsic proteins of pH 4.0- and pH 5.0-POB were 23 kDa and 38 kDa glycoproteins, the unknown proteins were 48 kDa and 60 kDa, while the 48 kDa and 38 kDa proteins were completely removed under the extraction condition of pH 6.0 and 7.0. The percentage of extrinsic proteins gradually decreased from 78.4% at pH 4.0-POB to 33.88% at pH 7.0-POB, while oleosin contents increased. The particle size and zeta potential of the POB emulsions decreased, whereas the oxidative stability, storage stability, and pI increased with the increasing extraction pH. QS (0.05~0.3%) increased the negative charges of all the POB emulsions, and 0.1% QS significantly improved the dispersion, storage, and the oxidative stability of the POB emulsions. This study provides guidance for selecting the proper conditions for the aqueous extraction of POBs and improving the stability of OB emulsions.

Lipid droplets are versatile organelles involved in plant development and plant response to environmental changes

Since decades plant lipid droplets (LDs) are described as storage organelles accumulated in seeds to provide energy for seedling growth after germination. Indeed, LDs are the site of accumulation for neutral lipids, predominantly triacylglycerols (TAGs), one of the most energy-dense molecules, and sterol esters. Such organelles are present in the whole plant kingdom, from microalgae to perennial trees, and can probably be found in all plant tissues. Several studies over the past decade have revealed that LDs are not merely simple energy storage compartments, but also dynamic structures involved in diverse cellular processes like membrane remodeling, regulation of energy homeostasis and stress responses. In this review, we aim to highlight the functions of LDs in plant development and response to environmental changes. In particular, we tackle the fate and roles of LDs during the plant post-stress recovery phase.

Oil body extraction from high-fat and high-protein soybeans by laccase cross-linked beet pectin: physicochemical and oxidation properties

BACKGROUND

Soybean oil bodies (SOB) are droplets of natural emulsified oil. Soybean oil emulsifies well but it is easily oxidized during storage. Beet pectin is a complex anionic polysaccharide, which can be adsorbed on the surface of liposomes to improve their resistance to flocculation. Laccase can covalently cross-link ferulic acid in beet pectin, and its structure is irreversible, which can improve the stability of polysaccharides.

RESULTS

At pH 2.5, laccase cross-linked beet pectin high-oil soybean oil body (HOSOB) and high-protein soybean oil body (HPSOB) emulsions showed obvious aggregation and severe stratification, and the oxidation of the emulsions was also high. The flocculation of emulsions decreased with an increase in the pH. The effect of pH on the flocculation of emulsion was confirmed by confocal laser electron microscopy. The ζ potential, emulsification, and rheological shear force increased with increasing pH whereas the particle size and surface hydrophobicity decreased with increasing pH.

CONCLUSION

This experiment indicates that the physicochemical stability of the two composite emulsions was strongly affected under acidic conditions but stable under neutral and weakly alkaline conditions. Under the same acid-base conditions, the degree of oxidation of HPSOB composite emulsion changes substantially. The results of this study can provide a basis for the design of very stable emulsions to meet the demand for natural products. © 2023 Society of Chemical Industry.

Extraction of structurally intact and well-stabilized rice bran oil bodies as natural pre-emulsified O/W emulsions and investigation of their rheological properties and components interaction

The isolated plant oil bodies (OBs) have shown promising applications as natural pre-emulsified O/W emulsions. Rice bran OBs can be used as a new type plant-based resource with superior fatty acids composition and abundant γ-oryzanol. This paper investigated the method of extracting structurally intact and stable rice bran OBs. Due to the adequate steric hindrance and electrostatic repulsion effects, rice bran OBs extracted by NaHCO₃ medium had smaller particle size, better physical stability, and natural structure. The protein profile of NaHCO₃-extracted rice bran OBs showed oleosin-L and oleosin-H, while exogenous proteins in PBS and enzyme-assisted- extracted rice bran OBs could interact with interfacial proteins through hydrophobic forces to aggregate adjacent OBs, further remodeling the OBs interface. It was also found that the small-sized rice bran OBs could adsorb on the interface of the larger-sized rice bran OBs like Pickering stabilizers. Rice bran OBs exhibited pseudoplastic fluids characteristic, but underwent a transition from solid-like to liquid-like behavior depending on the extraction method. The disorder of NaHCO₃-extracted rice bran OBs protein molecules increased their surface hydrophobicity. The random coil structure favored more proteins adsorption at the interface of rice bran OBs extracted by PBS. Enzyme-assisted extraction of rice bran OBs had the highest content of β-sheet structure, which facilitated the stretching and aggregation of protein spatial structure. It was also confirmed the hydrogen bonding and hydrophobic interaction between the triacylglycerol or phospholipid and proteins molecules, and the membrane compositions of rice bran OBs differed between extraction methods.

Physical and oxidative stability of astaxanthin microcapsules prepared with liposomes

BACKGROUND

Oil bodies (OBs) are a kind of natural and stable oil nucleate microcapsule in which the triglyceride matrix can be used as an appropriate carrier of hydrophobic molecules. Astaxanthin has high antioxidant properties but is extremely sensitive to oxidation, causing the loss of its bioactive properties.

RESULTS

The purpose of this study was to clarify the effects of environmental factors (light, oxygen, temperature, and pH) on the physical and oxidative stability of astaxanthin microcapsules prepared with peanut oil bodies (POBs). After 14 days of storage, the retention rate of astaxanthin in peanut oil microcapsules (POMs) was significantly increased. The astaxanthin retention rate of POMs stored under light conditions was higher than under dark conditions. Similarly, the retention rate of astaxanthin in POMs was significantly increased during vacuum storage. The astaxanthin retention rate was also the highest when POMs were stored at 4 °C, whereas it was the lowest at pH 3.0.

CONCLUSION

The experiment demonstrated that microcapsulation could improve the astaxanthin retention rate and storage stability, and recombinant OBs were potential ideal wall materials for astaxanthin embedding. © 2022 Society of Chemical Industry.

Plant oil bodies and their membrane components: new natural materials for food applications

Plants store triacylglycerols in the form of oil bodies (OBs) as an energy source for germination and subsequent seedling growth. The interfacial biomaterials from these OBs are called OB membrane materials (OBMMs) and have several applications in foods, e.g., as emulsifiers. OBMMs are preferred, compared with their synthetic counterparts, in food applications as emulsifiers because they are natural, i.e., suitable for clean label, and may stabilize bioactive components during storage. This review focuses mainly on the extraction technologies for plant OBMMs, the functionality of these materials, and the interaction of OB membranes with other food components. Different sources of OBs are evaluated and the challenges during the extraction and use of these OBMMs for food applications are addressed.

Oil bodies extracted from high-oil soybeans (Glycine max) exhibited higher oxidative and physical stability than oil bodies from high-protein soybeans

Reports concerning the characteristics of soybean oil bodies (SOBs) isolated from high protein genotypes and high oil genotypes of soybeans available in the literature are insufficient and limiting. In this study, fatty acid compositions, total phenol and tocopherol contents, antioxidant capacity, and physicochemical stability of SOB emulsions recovered from three high-protein and three high-oil genotype soybeans were comparatively investigated. Principal component analysis showed that all six SOB samples could be easily discriminated based on the cultivar characteristics. Overall, the SOBs derived from the high-protein soybeans exhibited higher polyunsaturated fatty acid (PUFA) contents, while the SOBs derived from the high-oil soybeans had higher extraction yields and tocopherol contents; the tocopherol content was also positively correlated with the antioxidant capacity of the lipophilic fraction, but the difference in the total phenolic content between the two genotypes was not significant. The SOBs derived from the high-protein soybeans were more easily oxidized during storage, with 1.38- and 4-fold higher accumulation rates of lipid hydroperoxides (LPO) and thiobarbituric acid reactive substances (TBARS), respectively, in the high-protein-derived SOBs than in the high-oil-derived SOBs. In addition, the SOBs from the high-protein soybeans exhibited pronounced coalescence during storage, which was corroborated by focused confocal microscopy. These results confirmed that SOBs obtained from high-oil soybean genotypes are more suitable to manufacture OB-based products due to their superior physicochemical stability.

Vitamin E in foodstuff: Nutritional, analytical, and food technology aspects

Vitamin E is a group of isoprenoid chromanols with different biological activities. It comprises eight oil-soluble compounds: four tocopherols, namely, α-, β-, γ-, and δ-tocopherols; and four tocotrienols, namely, α-, β-, γ, and δ-tocotrienols. Vitamin E isomers are well-known for their antioxidant activity, gene-regulation effects, and anti-inflammatory and nephroprotective properties. Considering that vitamin E is exclusively synthesized by photosynthetic organisms, animals can only acquire it through their diet. Plant-based food is the primary source of vitamin E; hence, oils, nuts, fruits, and vegetables with high contents of vitamin E are mostly consumed after processing, including industrial processes and home-cooking, which involve vitamin E profile and content alteration during their preparation. Accordingly, it is essential to identify the vitamin E content and profile in foodstuff to match daily intake requirements. This review summarizes recent advances in vitamin E chemistry, metabolism and metabolites, current knowledge on their contents and profiles in raw and processed plant foods, and finally, their modern developments in analytical methods.

Deciphering the properties of hemp seed oil bodies for food applications: Lipid composition, microstructure, surface properties and physical stability

Hemp seed oil bodies (HSOBs) are of growing interest in response to the demand of consumers for healthy and natural plant-based food formulations. In this study, we used minimal processing including aqueous extraction by grinding and centrifugation to obtain HSOBs. We determined the lipid composition of HSBOs, their microstructure, and the impact of the homogenization pressure, pH and minerals on their surface properties and the physical stability of the emulsions. HSOBs contain high levels of well-balanced PUFA with LA/ALA = 2.9, γ-tocopherol, lutein and phytosterols. The mean diameter of HSOBs was 2.3 ± 0.1 μm with an isoelectric point in the range of pH 4.4 to 4.6. Homogenization of hemp seed extracts induced a decrease in the size of HSOBs but did not eliminate the sedimentation of the protein bodies composed of the globulin edestin. By changing the surface properties of HSOBs, pH values below 6 and NaCl induced the aggregation of HSOBs, while CaCl₂ induced both aggregation and membrane-fusion mediated coalescence of HSOBs by involving probably the anionic phospholipids together with membrane proteins. This study will contribute to extend the range of novel food products and designed emulsions containing hemp seed proteins and oil bodies.

Chemical Characterization of Chinese Perilla Seed Oil

Physicochemical properties and chemical composition of Chinese perilla seed oil has been characterized in this study. The result showed that both the cold press oil and the solvent extracted oil possessed low acid value and peroxide value. The fatty acid composition result showed that the oil has high content of linolenic acid (C18:3) up to 66.4 g/100 g, followed by linoleic acid (C18:2) of 15.3 g/100 g. The total triacylglycerol (TAG) profiles results showed that the oil contained 20 TAGs including 17 regioisomers, including LnLnLn (35.8 g/100 g), LLnLn (20.2 g/100 g), LLLn (17.7 g/100 g) and PLnLn (14.9 g/100 g) (Ln, linolenic acid; L, linoleic acid; P, palmitic acid). With content of only 0.57 g/100 g oil, the unsaponifiable matters were mainly composed of phytosterols, squalene, tocopherol, alcohols and hydrocarbons. The total phytosterols content was 0.39 g/100 g oil, in which β-sitosterol has high content of 0.31 g/100 g oil.

Metal nanoparticles based lab-on-paper for phenolic compounds evaluation with no sample pretreatment. Application to extra virgin olive oil samples

In this work, a low-cost, disposable, and portable lab-on-paper device is proposed to simultaneously quantify total polyphenol content (TPC) and antioxidant capacity (AOC) in 15 min; the assay requires no pre-treatment of the samples. The lab-on-paper device fabrication has been carried out employing a xurography-based benchtop microfabrication technology using low-cost materials as chromatography paper and polymeric sheets. Extra virgin olive oil (EVOO) phenolic compounds' represents a nutritional added value, nevertheless, the high lipidic content hinders their direct and rapid analysis, resulting in an extremely challenging sample. The realized lab-on-paper allows to perform the dual TPC and AOC determination in three simple steps: (i) sample loading, (ii) analytes transport to the analysis spot, and (iii) double colorimetric analysis exploiting the growth of AuNPs and AgNPs on paper mediated by phenolic compounds. Signal acquisition is achieved using a standard digital camera. The dual colorimetric assay is able to detect phenolic compounds in the 25-500 mg L^-1 range with limits of detection ≤6 mg L^-1 and good reproducibility (RSDs ≤11%). Direct analysis of EVOO samples (n = 30) correlated well (r > 0.92) with conventional spectrophotometric methods for TPC and AOC determination.

Effects of pH on the Composition and Physical Stability of Peanut Oil Bodies from Aqueous Enzymatic Extraction

Peanut oil body (POB), which is rich in unsaturated fatty acids and bioactive substances, is widely used in cosmetics, food, and medicine. Compared with synthetic emulsifiers, peanut oil bodies have health advantages as natural emulsions. The physicochemical properties of oil bodies affect their food processing applications. To improve peanut oil body yield, cell-wall-breaking enzymes were screened for aqueous enzymatic extraction. The optimum conditions were as follows: enzymatic hydrolysis time, 2 h; material-to-liquid ratio, 1 : 5 ( $m/v$ ); enzyme concentration, 2% ( $v/m$ ); and temperature, 50°C. Oil body stability was closely related to pH. With increasing pH, the average particle size and zeta-potential of the oil bodies increased, indicating aggregation, as confirmed by microstructure analysis. At pH 11, exogenous proteins at the oil body interface were eluted, leaving endogenous proteins, which led to a decreased interfacial protein content and oil body aggregation. Therefore, oil body stability decreased under alkaline pH conditions, but no demulsification occurred.

Structure, assembly and application of novel peanut oil body protein extracts nanoparticles

Oil bodies (OBs), which are found mainly in the seeds or nuts of oleaginous plants, are spherical droplets with a triacylglycerol core covered by phospholipid-protein layer. Oil body protein extracts (OBPEs), mainly oleosins, contribute to the unique physicochemical stability of OBs. The application of OBPEs in aqueous environment has been greatly limited by their highly hydrophobic structures. In this study, OBPEs were successfully extracted from peanut seeds and their profiles were characterized by LC-MS/MS. OBPEs nanoparticles were successfully assembled in aqueous environment for the first time using the antisolvent precipitation method. The mean diameter of OBPEs nanoparticles was 215.6 ± 1.8 nm with a polydispersity index of 0.238 ± 0.005. The morphology of these colloidal particles was found to be roughly spherical shape as confirmed by transmission electron microscopy (TEM). Oil-in-water (O/W) Pickering emulsions with good stability against coalescence could be formed at protein concentration as low as 0.1 mg/mL. Cryo-scanning electron microscopy (cryo-SEM) confirmed that spherical nanoparticles were packed at the oil-water interface. This research will greatly expand the applications of OBPEs in structuring the interfaces and developing novel formulations in the food and pharmaceutical fields.

Composition and Rheological Properties of Peanut Oil Bodies from Aqueous Enzymatic Extraction

In this study, the relationship between the composition and rheological properties of peanut oil bodies from aqueous enzymatic extraction was evaluated. Aqueous enzymatic extraction using a combination of cellulase and pectinase at a 1:1 ratio effectively destroyed the structure of the cell wall and resulted in the maximum oil body yield of 90.7%. The microstructure and interfacial membrane composition of the peanut oil bodies were observed by confocal laser scanning microscopy. The oil bodies contained three inherent proteins (oleosin, caleosin, and steroleosin) along with two adsorbed foreign proteins (arachin and lipoxygenase). Five phospholipids were detected using ³¹P nuclear magnetic resonance spectroscopy. Among them, phosphatidylcholine, which plays a major role in the stability of oil bodies, was the most abundant. The measured rheological properties indicated that the oil bodies were a typical elastic system. Elevated temperature and high-speed shear destroyed the binding between proteins and phospholipids, reducing the oil body stability. The findings will facilitate the commercial application of peanut oil bodies by improving the extraction rate of peanut oil bodies and clarifying their stabilization mechanism.Practical Application: This paper studies the enzymatic extraction, composition and rheological properties of peanut oil bodies. It provides a theoretical basis for the large-scale application of peanut oil bodies in the food and cosmetic industries. It is beneficial to improve the application value of peanut resources.

Fate of phospholipids during aqueous extraction processing of peanut and effect of demulsification treatments on oil-phosphorus-content

PC (phosphatidylcholine), PE (phosphatidylethanolamine), PI (phosphatidylinositol), and PA (phosphatidic acid) in 9 peanut matrices obtained during the AEP (aqueous extraction processing) of peanut were quantified employing HPLC-ELSD analysis in this study. Phosphorus contents of crude oils obtained from different demulsification treatments were also investigated. Decantation had a larger effect than grinding in terms of phospholipids loss due to alkaline-hydrolysis, indicating this processing step was vital for the manipulation of phospholipids levels remained in oil. Over 80% of initial phospholipids were lost during AEP and only 19.8% of initial phospholipids ended up in cream, skim and sediment phase. 52.55% of the remained phospholipids trapped in cream phase. Just 22.16-32.61 mg/kg phosphorus content could be detected in crude oils, which indicated the separation of phospholipids from the cream phase into aqueous medium. Degumming was not essential in AEP of peanut and the waste generated after demulsification could be a source of phospholipids.

Effects of diacylglycerol and triacylglycerol from peanut oil and coconut oil on lipid metabolism in mice

Different chain lengths diacylglycerols (DAG) (long- and medium-chain) were synthesized from peanut and coconut oils. The effects of DAG with different chain lengths on body fat, blood lipids, and lipid metabolism-related enzymes in the liver and adipose tissue of C57BL/6J mice were investigated. Compared to peanut and coconut oils containing triacylglycerol (TAG), DAG-rich oils can significantly reduce the body weight, kidney weight, serum triglyceride (TG) content, hepatic fatty acid synthase (FAS), and Acetyl-CoA carboxylase (ACC) enzyme levels (p < 0.05) in C57BL/6J mice. Therefore, the effect of coconut oil DAG on improving body fat metabolism was probably due to the impact of DAG. Meanwhile, the body weight and serum TG content in coconut oil DAG group were lower than those in peanut oil DAG group. In addition, the spleen weight, hepatic ACC, and lipoprotein lipase (LPL) enzymes in coconut oil DAG group (0.07 ± 0.01 g, 2.08 ± 0.42 ng/mg pro, and 18.44 ± 5.23 ng/mg pro, respectively) were significantly lower than those in peanut oil DAG group. Although coconut oil DAG and peanut oil DAG have different fatty acid compositions, their effects on lipid metabolism showed no significant changes. Coconut oil DAG (peanut oil DAG) showed the improved lipid metabolism than that of coconut oil (peanut oil), which was probably due to the effect of DAG. PRACTICAL APPLICATION: Peanut and coconut oils are common edible oils. The oil containing DAG synthesized decreased the body weight and lipid accumulation in mice. Coconut oil is rich in medium-chain fatty acids, while peanut oil mainly consists of long-chain fatty acids. Due to the different contents of fatty acids, the synthesized structural lipids have different effects on lipid metabolism. Medium-chain triglycerides were considered as agents to alleviate obesity.

Identification of a caleosin associated with hazelnut (Corylus avellana L.) oil bodies

Caleosins are involved in several cellular and biological processes that are closely associated with the synthesis, degradation and stability of oil bodies (OB). Because of the importance and the multiple roles of these OB-associated proteins, in silico identification of sequences corresponding to putative caleosins in the hazelnut genome has been performed, and the association with seed OB was verified using a proteomic approach. Five full-length sequences (CavCLO-H1, CavCLO-H2, CavCLO-H3, CavCLO-L1, CavCLO-L2), belonging to the two groups of caleosins (H and L), have been identified in the hazelnut genome. The number of identified caleosins is in agreement with that previously observed in other plant species, confirming that caleosins comprise small gene families in plants. A proteomic approach allowed us to verify only the presence of CavCLO-H1 in hazelnut OB, suggesting that several members inside this family could have different roles during plant growth and development. In silico analysis also suggests that CavCLO-H1 may act as a peroxygenase.

Structure and functions of oleosomes (oil bodies)

Oleosomes are natural oil droplets, abundant in plants and more specifically in seeds, composing 20-50 wt% of their mass. The structure of oleosomes is the mechanism that seeds developed to safely store energy in the form of triacylglycerols and use it during germination. For this, the phospholipid/protein membrane that covers and protects the triacylglycerols has been wisely developed during evolution to grant them extreme stability against physical and chemical stresses. The remarkable property-performance relationships of oleosomes have generated a lot of interest to incorporate them in oil-in-water emulsions and take advantage of their sophisticated membrane. However, the structure-function relationship of the molecular components in the oleosome membrane is still not well understood and requires more attention in order to take complete advantage of their potential functions. The aim of this review is to give insights into the architecture of the oleosomes and to discuss the exploitation of their properties in advanced and broad applications, from carrying and protecting sensitive molecules to bio-catalysis.